Certain types of forgings, e.g. titanium turbine blade forgings, utilize glass lubricants during the forging operation. During this forging operation, a scale forms on the work piece. Thus, at the conclusion of the forging operation, it is necessary to remove both the scale which is formed and any remaining glass lubricant which has solidified on the surface of the parts. In certain cases, depending upon the particular glass composition, the remaining solidified glass can be reasonably quickly removed utilizing an oxidizing alkaline bath salt. Such a salt is sold under the trademark DGS by Kolene Corporation of Detroit Mich., which salt contains sodium hydroxide, potassium hydroxide, sodium chloride and sodium nitrate. However, with the more resistant type glasses, such as the boron-containing glasses, this type of salt is generally not aggressive enough to remove the glass and also perform the descaling in a commercially acceptable period of time.
Other types of salts which are available for deglassing which are more aggressive than the Kolene DGS salt are a group of salts sold by Kolene under trademark KASTECH CERAM-X. These salts contain hydroxides and fluorides, (either sodium or potassium hydroxides and sodium or potassium fluorides). These salts while being reasonably effective in removing even these relatively inert glass compositions, nevertheless have a drawback, especially when used on titanium, in that they tend to produce hydrogen pick-up in the work piece, which can be detrimental, especially in the case of titanium.
Thus, it is necessary to provide an aggressive descaling/deglassing salt which will act relatively quickly to both descale and deglass work pieces when more inert glasses are used, and also which will avoid hydrogen pick-up when used on titanium.